The present invention relates to roller chains used for driving conveyors and other movable devices. Accumulating conveyor chains are known. These chains generally include a roller which carries a product, and, when the products begin to back up on the conveyor, the rollers begin to rotate, allowing the products to sit on top of the chain while the chain continues to run, without creating a large back line pressure on the products. A problem that can be encountered with such chains is that, if a substantial driving force is needed to move the products, the rollers may begin to rotate too soon, so that the products are not moved by the conveyor. Prior art accumulating conveyors generally do not allow control or adjustment of the threshold force at which the rollers begin to rotate.